Pros:
This course offers wonderfully challenging and varied disc golf options. With two tees and two permanent baskets on every hole, you can play P'tap as anything from a challenging ~4,900' par 3 course to an intimidating ~9,000' par 63 monster. Terrain features rolling hills, steep drop-offs, mature woods, park-style areas, and a couple of open or semi-open holes. This course offers something for everyone - there are even rec tees marked by painted bricks.
Green baskets are permanently set in the long ("C") position, and the grey baskets are rotated between the "A" and "B" positions. Baskets are well mounted, level, and catch well. Two 9-hole loops, both starting and finishing near the parking lot.
This is where I go locally when I want to see discs fly. Patapsco offers plenty of opportunities to bomb a big downhill drive through the trees, and plenty of tricky approaches with drop-offs past the basket. A few holes feature pucker-inducing drop-offs alongside the fairway if your drive kicks sideways.
Well-maintained indoor restrooms are located between holes 3 and 4 near the parking lot, and between holes 10 and 11. The latter restroom has an outside drinking fountain available during warm weather months. Port-a-pot also located near the parking lot and hole 4 long tee.
Cons:
No tee signs or directional signs. This can make navigation and basket location very difficult for first-time players, especially since the long baskets are usually blind from the tee. If you cannot find a local guide, make sure to have a map available the first time you play here.
Teepads are made from stone dust. When maintained and leveled they are some of my favorite teepads to throw from. If they are not maintained a divot develops near the front left of the pad where righty backhanders plant, and sometimes this divot fills with water. If you don't have a long run-up you can simply start a little further back - a few extra feet on a 500' hole doesn't make much difference. Tees have been well maintained recently.
Green baskets can be hard to spot during the growing season, but stand out nicely during fall and winter. Long grass or rough beside the fairways can eat discs on a few holes, especially in late summer.
The back 9 plays around a large open area that is used for Boy Scout gatherings. You can still play when the Scouts are active, but please be careful and considerate.
Currently there is no practice basket. There used to be one but it was removed for a playground.
Other Thoughts:
Patapsco Valley is a difficult course to rate. Having played it many times, for me it is easily a 4.5 course that can challenge and entertain everyone from hackers to touring pros. But if you are playing the course for the first time you may find the lack of signs and blind long baskets frustrating and consider the course more of a 3.5. On balance I am giving the course a 4.0.
For first-timers I strongly suggest using a map AND playing a quick short-to-short round to scout out landing zones and long basket locations. No one ever follows this excellent advice, but my rating will make more sense if you do.
Traditionally, Seneca Creek and Patapsco Valley were the yin and yang of Maryland disc golf. Seneca Creek challenged your ability to shape lines, while Patapsco Valley challenged your ability to throw bombs up and down big hills in the woods. Together, the two courses offer a remarkably complete spectrum of disc golf challenges.
Play long tees to long baskets for the full "Green Monster" experience, and prepare yourself for the mental strain of relentless distance. Playing short tees to long baskets (~7,900') offers slightly more manageable distances, but requires you to hit an early gap on several holes.
Regardless of which tee you play, the long baskets make the course special. If a long technical approach with a steep drop-off near the basket does not sound like a fabulous disc golf experience, Patapsco Valley might not be the right course for you to play. For me, Patapsco has excellent replay value because most long baskets require two drives (or more) to reach, so your second (third, etc.) shots provide a different adventure every time.
The back 9 starts with three fairly open holes, giving you a chance to warm up and dial in your throws. I often play the back 9 first for this reason, but both loops have excellent finishing holes. I prefer finishing on holes 7 (long, technical), 8 (big downhill tunnel), and 9 (downhill bomb through big trees and then uphill to a beautiful rocky wooded green). But the finishing holes on the back nine - holes 17 (technical and dangerous) and 18 (big downhill bomb followed by a technical approach) are no slouches.
There is no water in play on the course, but park roads that cross the fairway play as OB "rivers." Where park roads run alongside the fairway, typically the road and beyond are OB. One may occasionally have to wait for a car to pass before throwing, but generally there is not much traffic on park roads.
Lots of other activities are available at the park and nearby. If you follow the trail past the parking lot between holes 1 and 2, you can hike along the Patapsco River falls. Downstream of the falls the rocky river is a great place to hike or cool off an overheated dog. The nearby Turf Valley shopping center offers ample dining opportunities and a grocery store.
The park charges a nominal entry fee.